Synergistic fungicidal mixtures of chloro phenols and pyrones for preserving vegetable fibers



United States Patent SYNERGISTIC FUNGICIDAL lVIlXTURES OF CHLORO PHENOLS AND PYRONES FOR PRESERVING VEGETABLE FIBERS Jose Polak, Mexico City, Mexico, assignor to Polaquimia, Sociedad Anonima de Capital Variable (S. A. de C. V.), Mexico City, Mexico, a corporation of Mexico NoDrawing. Application April 25, 1955 Serial No. 503,802

14 Claims. (Cl. 167-385) The present .invention is concerned with novel compositions and methods for protecting and preserving vegetable fibers, such as sansiviera, kenaf, abaca, jute, hene' quen, flax, sisal and other hard fibers, from decay and similar deterioration.

The use of such vegetable fibers for the production of twines, cordage materials, fabrics and the like is well known. Generally speaking, the leaves of the fiber plant arecut and decortic'ated so as to separate the fiber from pulp, skin, juice and other materials associated therewith. Thereafter the fiber is processed into the desired product by appropriate combing, spinning and weaving operations. During the combing, the fibers are normally impregnated with a lubricating oil, e. g., about by weight, which is a petroleum lubricating oil, if they are to 'be made into twines for agricultural purposes. The oil is utilized in order to make the cordage more pliable and to protect the same against the efiects of moisture. In other cases, where the fiber yarns are used for purposes not subject to outdoor conditions, optical bleaches and/ or wool grease may 'be applied to the yarns.

Deterioration of the cellulosic content in these vegetable fibers has presented a very serious problem. For instance, cordage made from sisal hemp decays and, as a result, loses its strength and breaks easily. This is particularly serious in connection with agricultural twines and marine cordage.

To obviate this difiiculty, numerous preservatives and the like have been proposed for application to the fibers, either before, during, or after they have been processed into the finished product, but none of these prior preservatives has been satisfactory. For example, the materials most frequently used as preservatives for these fibers are coal tar derivatives, such as creosote, cresylic creosote or cresylic acid, usually diluted with a pertoleum solvent,

typical of which are kerosene, gas oil, naphtha and the like. The principal reason for using these coal tar derivatives is that most of these materials possess an odor which was believed to effect a repelling action against insects and rodents. However, it has been found that no such repellency is actually demonstrated by these materials. Additionally, since these derivatives are usually applied in diluted form, the odor of these materials is not lasting and water soluble derivatives tend to leach out, particularly when in contact with water and in rainy or humid climates. Furthermore, when these coal tar derivatives, either alone or dissolved, are applied to the fibers, a clogging of the combing and spinning machines occurs to such an extent that stoppage for cleaning purposes is continu ously necessary.

Another disadvantage of the use of these coal tar derivatives is that they tend to substantially lower the breaking and/ or resistance strength of the fiber yarn. Apparently these materials, especially when diluted with petroleum products, have a solvent action on certain natural pectins, gums and resins in the fiber. The individual filaments of the fiber are held together by such natural pectins, gums and resins and necessarily, if the latter are attacked by solvent action, the yarn is weakened.

2,849,360 Patented Aug. 26, 1958 ice To be completely satisfactory, a' preservative composicharacteristics 1) It must be economical and within the limits allowed in the customary process of manufacture;

(2) It must not cause a reduction in resistance, such as breaking strength of the finished product, but rather enhance it;

(3) It must be capable of inhibiting and/ or killing any and all micro-organisms responsible for the degradation, deterioration or destruction of the fibrous product after a reasonable period has elapsed from the moment the preservative composition is applied;

(4) It must be capable of protecting'the finished product from subsequent contamination by destroying micro organisms whether soil born or aerobic;

(5) It must not contain any substance harmful to human beings or animals;

(6) It must not precipitate in the lubricating oil or other solvent, nor cause other ingredients to be precipitated, at the expense of its properties and activity;

(7) It must not increase or darken the natural color of the solvent so that it stains the final cordage, to any appreciable extent;

(8) It must be of a lasting nature, at least sufiicient to allow for a carryover of the finished products from, for example, one season to another as well as, in storage, thus avoiding losses due to market conditions;

(9) It should be irreversible, that is, although the concentration of the preservative composition present in the fibrous products may not have a definite lethal etfect on the prevailing micro-organisms, it should not permit a recuperation of these organisms, much less cause them to return to virulence or activity;

(10) It should be capable of preserving the natural brilliance of the fibers and not cause same to become opaque, but rather enhance the lustrous aspect thereof;

(11) It should not leach out of the fibrous products regardless of the amount of water of humidity with which it comes into contact, nor should it be soluble in water when exposed to atmospheric conditions;

(12) Besides being an efiicient fungicide, it should also have insecticidal and germicidal properties as well as being fungistatic and bacteriostatic in reduced concentrations;

('13) It should have no odor unpleasant to the users, nor contaminate agricultural produce with which it comes in contact;

(14) It should be applicable as a preservative equally to the raw fiber as Well as to products made therefrom, such as cordage, bags, cloth, cable, canvas, sail-cloth, awnings, hammocks, tarpaulins, tents, textiles and other products manufactured from this type of cellulosic fiber, and it should be capable of protecting materials such as corn and the like when packed in bags made from the fiber; and

(15) It should contain substances which are non-volatile or become non-volatile when converted into the finished composition.

None of the preservatives previously used has all or even a substantial number of the above-mentioned characteristics. Coal tar derivatives, as mentioned, lack several of these characteristics. Other well known preservatives, such as copper and zinc naphthenate, chlorinated naphthalene and phenol, are likewise unsatisfactory.

The principal object of the present invention is to provide novel compositionsand methods for preserving vege- Other objects will be apparent from the detailed description of the invention given hereinafter.

The foregoing objects are realized by applying to vegetable fibers of the type discussed a composition comprising two or more specific chlorinated phenols and/ or at least one pyrone compound of the type defined in U. S. Patents 2,229,204, 2,653,943, 2,653,944 and 2,653,945. Preferably, preservative compositions according to the invention comprise both one or more of the designated pyrones and two or more of the chlorinated phenols mentioned below. However, it is also possible to obtain satisfactory results by using either component singly.

The success of the invention is due to the discovery that the deterioration of hard vegetable fibers is actually due to certain fungi and other micro-organisms and that the pyrone compounds mentioned above and/ or certain mixtures of chlorinated phenols are specifically effective against such destroying organisms.

The discovery that the hereinafter designated chlorinated phenols and/or the pyrone compounds can effectively preserve fibrous products is surprising for a number of reasons. For instance, many known preservatives, e. g., certain coal tar derivatives, do not appear to have any effect whatsoever in avoiding the deterioration of vegetable fibers. Additionally, it appears that when a mixture of specific chlorinated phenols is used alone or together with the pyrone compounds, a synergistic effect is obtained which consists of a greater preservative action than the sum of the action of the individual compounds. In other words, the chlorinated phenols in the phenol mixture with or without the pyrone compounds supplement each other with the result that remarkably small amounts thereof can be effectively used to preserve the fibrous products. These unique results are particularly apparent when the pyrone or pyrones and mixture of chlorinated phenols are used together. The remarkable effectiveness of the present compositions is emphasized by the fact that these compositions are at least twenty times more effective than, for example, copper naphthenate, which is considered one of the best preservatives hitherto available. This means that substantially less of the present products may be used to obtain the same results.

The unique results of the invention can be obtained with any two or more of the following chlorinated phenols and water-soluble salts thereof, e. g., the sodium and potassium salts: 2,4,5-trichlorophenol; 4-chloro-2-phenylphenol; 6-chloro 2 phenyl-phenol; 2,3,4,6-tetrachlorophenol; and pentachloro-phenol. Of these, the 2,4,5-t1ichloro-phenol is the most effective preservative and fungicide. Other chlorophenols of relatively high volatility may also be included with the above chlorinated compounds for the purpose of repelling insects and rodents if such repellent action is desired.

As mentioned above, any of the pyrone compounds described in U. S. Patents 2,229,204, 2,653,943, 2,653,944 and 2,653,945 are suitable for use. Preferably, however, the pyrone compound is 3-acetyl-6-methyl-pyrandione-2,4, whether in its enolic or keto form, or one of the watersoluble salts thereof, such as the sodium and potassium salts. The preferred pyrones have been found to provide a maximum preservative action, particularly when used in conjunction with two or more of the designated chlorinated phenols. The pyrone compounds are essentially of ;a neutral nature and do not alter the pH of the lubricating oil or other organic vehicle therefor. These pyrones are odorless and tasteless and soluble in any proportion in the media employed for the purpose, and they represent no hazard to animals in the concentrations at which they are used for the purpose outlined.

The preservative compositions of the invention may be applied in any convenient manner to the fibrous material, either before, during or after the processing of same. Preferably, however, they are incorporated in the combing operation with the lubricating oil or other appropriate vehicle, e. g., glycols or glycol esters. To this end, the

pyrone and/ or mixture of chlorinated phenols is dissolved or emulsified in the vehicle and the resulting l1 qu1d composition sprayed or otherwise uniformly applied to the fibers. The pyrones are normally solid and m those cases where they are to be admixed with chlorinated phenols which are also solid, such as 2,3,4,6-tetrachloro-phenol, 2,4,5-trichlorophenol and pentachloro-phenol, the solid materials are preferably mixed together and the vehicle heated to obtain the desired incorporation. Where heating of a vehicle is not convenient and operations carried out in the cold are preferred, at least one naturally liquid chlorinated phenol, i. e., 4 or 6-chloro-2-phenyl-phenols or both, should be used to which the sohd chlorinated phenols and/ or pyrones are added with or without the use of a vehicle for dilution purposes.

It has been observed that the abovementioned synergistic etfect is obtained to a noticeable degree if the content of any one of the chlorinated phenols 111 the nnxture thereof does not exceed 99% by weight of the mixture. Optimum proportions in any instance, however, depend upon the economics involved, the fibers belng treated, the specific chloro phenols utilized, i. e., whether hquid or solid, and other like factors. Where one or more pyrones are included, the compositions should comprise as essential active preservative, at least 0.5% and up to 5% by weight of pyrone and from 99.5 to 95% by weight of mixed chlorinated phenols. More than 5% of the pyrone can be included in the composition, although this is not necessary, 1% being preferred.

The amount of chlorinated phenols and/ or pyrone compound or compounds which must be applied to the fibers to preserve the same, according to the invention, can be rather widely varied. However, as noted above, one of the principal advantages of the invention is that the fibers may be effectively preserved using very small amounts of these materials. Accordingly, as little as 0.005% of the active preservative, based on the dry weight of the fibers, will retard micro-organism growth. Additionally, when the preservative does not include a mixture of chlorinated phenols, i. e., it is essentially one or more pyrones, a minimum of about 0.01% will inhibit growth of micro-organisms. When the preservative does not include any of the pyrone compounds, it will inhibit micro-organism growth at a concentration as low as about 0.08% on the dry weight of the fibers, while a minimum of 0.05% is sufiicient to inhibit in the case where the preservative comprises both one or more pyrones and a mixture of chlorinated phenols. Larger amounts than those stated can be used. For example, as much as 0.5 by weight of the dry fibers of chlorinated phenols may be utilized, but it is generally preferred, for economic reasons, to utilize the minimum amount consonant with the degree of contamination to which the fibrous materials will be exposed.

As indicated above, it has been found that deterioration of the vegetable fibers is due to certain fungi or micro-organisms present in the raw fibers. For instance, study of raw henequen fiber shows, among others, the following micro-organisms to be present therein:

The abovementioned micro-organisms were shown to degrade the fiber as follows:

The raw fiber was cultivated in a Dextrosed Saboroud culture media (Diffco) at room temperature (about F.). The fiber started deteriorating in about three days and was completely degraded in thirty days.

A batch of completely deteriorated henequen fiber in the form of twine which had been impregnated with a copper fungicide at "the time {the ftwine was spun was analyzed in the manner discussed above and showed the following additional micro-organisms present:

(11) Asp ergillus cla'vwtus ('12) Aspergillus. fumigatus (13) Aspergillus ustus (14) Aspergillus (various species) 15 Chaetomium globosum.

(16) Chaetomium (various) (17) F usam'um oxysporum (18) Some species of Cladisporum, Curvularia and Stemphylium not otherwise identified.

Tests were carried out on twine treated with various concentrations of coal tar derivatives, using as test cultures various of the microorganisms noted above. The results of these tests showed that these derivatives possess no fungicidal qualities or preservative action and are incapable of inhibiting growth of the micro-organisms. In contrast, comparative tests using a mixture of chlorinated phenols according to the invention and 3-acetyl- 6-methyl-pyrandione-2,4 show such composition effectively inhibits micro-organism growth and otherwise preserves the fiber.

The invention is further illustrated by the following specific example which should not be considered as limiting:

Example Compositions designated as A and comprising 3- acetyl-6-methyl-pyrandione-2,4 diluted in cordage oil in proportions of 0.05%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 2.0%, 3.0%, 4.0% and 5.0% by weight of the pyrone compound were prepared.

Since of this cordage oil was subsequently incorporated in the fiber cordage, the resulting quantities of the active principle is one-tenth of these concentrations, expressed in terms of the dry weight of the cordage, thus resulting in final concentrations of- 0.005%, 0.01%, 0.02%, 0.03%, 0.04%, 0.05%, 0.1%, 0.2%, 0.3%, 0.4% and 0.5%.

There also were prepared eleven compositions B consisting of a mixture of 90 parts of pentachloro-phenol and 10 parts 2,4,5-trichloro-phenol diluted with cordage oil in the same concentrations as noted above for solutions A.

Eleven different compositions C were prepared by admixing about 47 parts 4-chloro-2-phenyl-phenol, 47 parts 6-chloro-2-phenyl-pl1enol, 5 parts 2,3,4,6-tetrachloro-phenol and 1 part 3-acetyl-6-methyl-pyrandione-2,4 in cordage oil using the proportions of compositions A and B.

Three sets of eleven samples of henequen (sisal hemp) fiber were employed, plus three specimens which served as controls. The three sets of eleven specimens each were impregnated with the various concentrations of compositions A, B and C and placed in Petri dishes for the period of 72 hours with the purpose of having the preservatives containing oil penetrate into the specimens.

At the end of the 72 hour period, all of the samples were placed in test tubes separately, using as culture media Diifco Dextrosed Saboroud and subjected to the prevailing temperature and relative humidity. The three control samples were also placed in the test tubes in the same manner.

On the third day, the three control samples showed abundant colonies of micro-organisms of the types noted above as (1) to (10), all of them covering the inside of the tubes which remained in an inclined position in the racks.

In;the case of compositions A, the test tubes containing 0.005% of the active principle showed a retarded growth of micro-organisms on the fifth day from the beginning of the tests. The test tubes containing from 0.01% and up did not show any growth of mirco-organisms at the end of the thirty day period.

In the case of compositions B the test tubes containing from 0.005% up to and including 0.07% of the active principles showed-a retarded growth of micro-organisms on the fifth day from the beginning of the tests, While all other tubes containing from 0.08% and up remained negative.

In the case of compositions C, the test tubes containing concentrations of the active principles from 0.005% to 0.04% presented on the fifth day retarded development and growth of micro-organisms, while the tubes containing from 0.05% and up remained neutral, and did not show any growth of micro-organisms whatever at the end of the thirty day period.

All of the concentrations were calculated, based upon the dry weight of the fiber, and all test tubes were subjected to prevailing room temperature of about F. and RH (relative humidity) of about 70% While the foregoing example is specific to the treatment of sisal hemp, with respect to which the invention is especially important, particularly for the purpose of avoiding deterioration of cordage made therefrom, it will be appreciated that the invention is also applicable to the other hard fibers mentioned above using any of the compositions encompassed by the appended claims wherein I claim:

1. The method of preserving vegetable fibers which comprises applying thereto a mixture comprising (a) at least two chlorinated phenols selected from the group consisting of 2,4,5-trichloro-phenol, 4-chloro-2-phenylphenol, 6-chloro-2-phenyl-phenol; and (b) a pyrone compound synergistic with said chlorinated phenols, wherein said mixture consists essentially of from 0.5% to 5% by weight of said pyrone compound and from 99.5% to by weight of said chlorinated phenols.

2. The method of claim 1 wherein said phenols are used in the form of water-soluble salts.

3. The method of claim 1 wherein said fibers are selected from the group consisting of sansiviera, kenaf, abaca, jute, henequen, flax, and sisal.

4. The method of claim 1 wherein said fibers are sisal hemp.

5. The method of claim 1 wherein said synergistic mixture is applied as a solution.

6. The method of claim 5 wherein said mixture is applied as a solution in lubricating oil.

7. The method of claim 1 wherein said pyrone compound is selected from the group consisting of 3-acetyl- 6-methyl-pyrandione-2,4 and the water-soluble salts thereof. I

8. The method of claim 1 wherein as a synergist at leastv 005% of said mixture, based on the dry weight of fiber, is applied to said fiber.

9. A fungicidal composition comprising a mixture of (a) at least two chlorinated phenols selected from the group consisting of 2,4,5-trichloro-phenol, 4-chloro-2- phenyl-phenol, 6-chloro-2-phenyl-phenol, 2,3,4,6-tetrachloro-phenol, and pentachloro-phenol and (b) a pyrone compound synergistic with said chlorinated phenols, wherein said compositions consist essentially of from 0.5% to 5% by weight of said pyrone compound and from 99.5 to 95% by weight of said chlorinated phenols.

10. The fungicidal composition of claim 9 wherein said pyrone compound is selected from the group consisting of 3-acetyl-6-methyl-pyrandione-2,4 and the watersoluble salts thereof.

11. The fungicidal composition of claim 9 wherein said phenols are in the form of water-soluble salts.

12. The fungicidal composition of claim 9 containing 7 about 1% pyrone and 99% of said chlorinated phenols.

13. Vegetable fibers treated with the fungicidal composition of claim 9.

14. Sisal hemp fibers treated with the fungicidal composition of claim 9.

References Cited in the file of this patent UNITED STATES PATENTS 2,071,822 Ellis Feb. 23, 1937 2,142,604 Carswell Jan. 3, 1939 2,304,013 Norton Dec. 1, 1942 O 0 2,486,961 Meyer Nov. 1, 1949 2,567,010 Coleman et al. Sept. 4, 1951 FOREIGN PATENTS 685,331 France July 9, 1930 672,459 Great Britain May 21, 1952 OTHER REFERENCES Frear, Catalogue of Insecticides and Fungicides, 1948, Chronica Botanica, Waltham, Mass., vol. 2, pp. 39 and 99. 

